Welcome to the Q&A Forum

The interstitial update only affected mobile browsing, from what I can remember. This popup doesn't appear on their mobile site and thus, I would assume it shouldn't have any impact. However, I would recommend increasing the wait time to pop the message up,  so that it acts as a form of help to a user, rather than blocking their browsing immediately.

Thanks for helping Dirk!

If it is unlikely that a webmaster will reply or looks as though the site is trying to hide contact details then you may not need to contact webmasters before disavowing as it is a waste of time. But in a lot of cases it is more beneficial to you to have a bad link removed than to just disavow it, so it can be worth contacting a webmaster to remove a link. If you are under a penalty though, Google will want to see you are doing everything you can to remove unnatural links and may want to see evidence that you are trying to contact webmasters to remove links rather than just putting everything into a disavow file, because links that are disavowed can just be taken out of the disavow file and be 're-avowed'. Kind Regards

1. Yes 2. Using google analytics 3. Google organic search. 4. It's not site wide but it's prevalent on pages that we did not do the AJAX change to Thanks!